The aim of the study is to present the results of research aimed at comparing the level of self-regulation of behaviour in children and adolescents in the natural and institutional environment. Institutionalisation occurs over a period of time in children and adolescents living in institutions. We can frequently observe the symptoms of institutionalisation in these groups of children and adolescents, which is a major obstacle to their functional self-regulation of behaviour and to their return to the natural social environment. The research sample was comprised of 2,776 children and adolescents from the natural and institutional environment in the Czech Republic (children and adolescents living in total institutions such as correctional institutions for children and minors and children's homes). The Self-regulation Questionnaire (SRQ) used in the study contained 12 items aimed at 3 areas of self-regulation of behaviour: Affect, Awareness and Empowerment. The results have shown that the level of self-regulation of behaviour is lower among children in the institutional environment. We recorded the most significant differences between children from the institutional and natural environment in the area of Affect (i.e. the regulation of emotions). It means that children and adolescents from institutional environments have more trouble controlling their emotions than children from a natural environment. We also found that the level of self-regulation of behaviour is dependent on the perceived level of problematic behaviour of children and adolescents. A higher level of problematic behaviour of children and adolescents indicates a lower level of self-regulation of their behaviour. We also found that differences in the level of self-regulation of behaviour, depending on the perceived degree of problematic behaviour, are not significant in either type of environment. It means that the perceived degree of problematic behaviour is reflected in the level of self-regulation of behaviour in a similar way in the natural and institutional environment. (C) 2016 Published by Elseiver Ltd. This is an open access article under the CC BY-NC-ND license.